共查询到20条相似文献,搜索用时 171 毫秒
1.
异氰酸酯胶在刨花板中的应用 总被引:3,自引:1,他引:3
异氰酸酯胶作为刨花板胶粘剂,具有刨花含水率适应范围广(0~25%),施胶量低、无游离甲醛释放、适合制造轻质刨花板等优点。施胶量为5%、密度为0.45g/cm3和0.61g/cm ̄3的二苯基甲烷二异氰酸酯(MDI)小黑杨刨花板的物理力学性能分别达到A类刨花板二等品和优等品的指标要求。密度为0.65g/cm ̄3时,只要MDI施胶量达到3%,刨花板的物理力学性能指标能达到A类刨花板的国家标准要求。试验还表明:MDI具有较好的耐水性,但耐湿热性和长期耐水性不如酚醛胶。生产1m ̄3刨花板MDI与PF和UF胶粘剂成本比为2.05:1.78:1.00。 相似文献
2.
改性UF麦秸均质刨花板的工艺研究 总被引:1,自引:1,他引:1
通过试验确定了麦秸均质刨花板的主要工艺参数。其结果表明:10mm厚麦秸均质刨花板的较优工艺参数为热压温度150℃、热压时间8min、表层麦秸刨花的施胶量为10%、芯层麦秸刨花的施胶量为8%、板密度0.75g/cm3、表芯层刨花比例为3:7。按照以上工艺条件压制的麦秸均质刨花板性能已达到均质刨花板的要求。 相似文献
3.
通过对杂交杨w-14密度试验所产种条、苗木的生物量测算、内含物(还原糖、全氮等)测定、育苗、造林试验,确定了生产种条的合理密度为7~14株/m2,平茬苗(Ⅰ(2)-0)的合理密度为3~6株/m2;合格种条的标准是地径(离地5cm)、D5>1cm,D5/H>0.006,全条皮干重(W)在(W)d11.7g以上,还原糖含量在44mg/g左右,合格苗木的标准是:地径(离地6cm)D6>1.5-2.0cm,地上部皮干重为31g或39g以上,上段皮还原糖含量在45.8mg/g以上。 相似文献
4.
板栗木材密度和直径生长的研究 总被引:6,自引:4,他引:2
本文通过对板栗木材密度与年轮宽度的研究表明,板栗木材年轮宽度较窄,为0.21cm,近髓心宽度较大,后期呈较平衡的下降趋势;年轮密度从髓心向外一直呈逐渐下降趋势;平均木密度为0.6164g/cm^3,最大密度为0.7785g/cm^3,最小密度为0.3774g/cm^2,早材密度0.4835g/cm^3,晚材密度0.6821g/cm^2,变异幅度0.439,密度梯度23.6978,木材面向密度为0. 相似文献
5.
异氰酸酯胶芦苇刨花板生产工艺研究 总被引:11,自引:0,他引:11
芦苇的SiO2含量高,使用脲醛胶(UF)难以获得良好的胶合结果,本研究采用二苯基甲烷二异氰酸酯(MDI)胶粘剂压制芦苇刨花板,试验结果表明,当MDI施胶量为4%和5%,刨花板的密度为0.70g/cm^3时,其物理力学性能指标分别达到我国A类刨花板优等品种和二等品的标准要求,如果MDI单价由现在20.00元/kg下降到17.30元/kg,MDI芦苇创花板和UF芦苇刨花板的生产成本相同。 相似文献
6.
研究表明黑荆木材1—3年生密度为0.59—0.65g/cm3,5—10年生为0.72g/cm3;1—7年生木材成分变化不大,纤维素在45%以上,半纤维素在25%以下,木素在21%以下。比较6年生黑荆木材及其KP、CTMP的纤维形态,纤维长度在0.76mm以上的,木材为72.04%、Kp为72.22%、CTMP为82.58%;平均纤维长度木材为0.856mm、KP为0.845mm、CTMP为1.165mm;纤维宽度在12一24μm,木材为92.62%、KP为92.86%、CTMP为34.63%;平均纤维宽度木材为15.6μm、KP为15.8μm、CTMP为30.7μm;长宽比木材为54.9、KP为53.3、CTMP为37.9。 相似文献
7.
对废纸刨花板的制造工业进行了初步探讨,分析了废纸用量,施胶量,热压时间,热压温度4个变量因子对刨花板性能的影响。试验结果表明添加部分废纸制造刨花板是完全可行的,其产品主要物理力学性能,密度(ρ)0.75g/cm^3,吸水厚度膨胀率(TS)3.8%,内结合强度(IB)0.62MPa,静曲强度(MOR)22.4MPa弹性模量(MOE)25.4×10^3MPa均达到GB/T4897-92中B类刨花板的技 相似文献
8.
在山杨主要分布区随机抽取6个天然群体,每群体随机抽样15株采集木芯,分析结果表明:群体间及个体间的木材密度和纤维长度差异都极显著。群体平均密度0.432lg/cm3,极差0.0662g/cm3;平均纤维长度1.0775mm,极差0.2650mm。东北、华北群体的密度呈梯度变异,纤维长度的梯度变异不明显。木材密度群体重复率0.541,个体重复率0.471;纤维长度重复率分别是0.471与0.412。不同群体、不同年轮组的密度与纤维长度的个体重复率有所不同。密度、纤维长度等与生长性状呈微弱遗传相关,可以进行材性与生长的同步遗传改良。 相似文献
9.
10.
本文对8203号和木材基本性质进行了测定,其结果:基本密度0.345g/cm^2;气干密度0.40g/cm^2;干缩系数0.36;纤维长度1337μm,长宽比51;综纤维素含量80%。8203号杨适宜制作各种板材及建筑用材,同时也是较理想的制浆、造纸材种。 相似文献
11.
12.
YU Wenji REN Dinghua MA Hongxia ZHOU Yue Research Institute of Wood Industry Chinese Academy of Forestry Beijing P.R.China 《中国林业科技(英文版)》2005,4(2):66-74
China is one of the major production countries forwood-based panel products, and its production wasranked in the second place in the world in 2003. Onthe other hand, however, China is also a country withshortage of forest resources. As the main raw material,wood supply is becoming a serious problem with thefast growing of panel production. Fortunately, thereare plenty of agricultural residues in China, and thisgives the possibility to use agri-based fibers instead ofwood. Many wood-based pane… 相似文献
13.
We investigated the bending properties of composite boards produced by reinforcing both sides of corrugated particleboard with medium-density fiberboard (MDF). Thickness swelling and linear expansion (LE) were measured to assess the dimensional stabilities of the composite board. Although the apparent density of the composite board was 0.48g/cm3, its strength was found to be equivalent to that of 18-type particleboard as described in JIS A 5908. The boards parallel/perpendicular anisotropy in strength was 0.9. The modulus of rupture (MOR) of the composite board increased with board density only up to a certain density, beyond which the MOR was constant. On the other hand, the thickness swelling of both corrugated particleboard and the composite board was smaller than that of flat-type particleboard, satisfying the JIS A 5908 standard of 12%. Linear expansion (soaking in water of ordinary temperature for 24h) of corrugated particleboard was 0.7%–0.9% in the parallel direction and 2.1%–3.1% in the perpendicular direction; hence, anisotropy in linear expansion existed in the corrugated particleboard. The linear expansion of the composite board was 0.6%–0.9% in the parallel direction and 1.8%–2.5% in the perpendicular direction. Although the LE of the composite board was lower than that of corrugated particleboard, it is necessary to improve the LE of composite board for practical use. 相似文献
14.
15.
16.
以废旧建筑模板和家具为原料,使用环保型无机胶黏剂制备刨花板。利用扫描电子显微镜(SEM)观察刨花板的微观形貌,同时利用量热仪、氧指数测定仪、同步热分析仪等评价板材的阻燃性及热稳定性。结果表明:当板材密度为0.95g/cm^3时,除24h吸水厚度膨胀率外,其余物理力学性能均符合国标中的P3型刨花板要求;SEM观察到无机胶黏剂包覆刨花,填充板材孔隙,使板材物理力学强度大幅提高;选择氯化镁为固化剂,当表层/芯层刨花的固化剂用量为4.5%/5.0%时,压制的密度为0.95g/cm^3的刨花板,其氧指数为31%,具有较好阻燃性能。 相似文献
17.
The interaction between particle size and resin content is one of the most important structural parameters that can influence the accuracy of predictions about wood-composite properties. We developed three kinds of equation (linear, quadratic, and exponential) for each mechanical property of particleboard based on slenderness ratio and resin content at a constant density (0.7g cm -3 ). Results from SHAZAM software (version 9) suggested that the quadratic function was not significant, but the linear and exponential functions were significant. The interaction between particle size and resin content was analyzed by Maple 9 software. The results indicated that an exponential function can better describe the simultaneous effect of slenderness and resin content than a linear equation. Under constant resin content, particles with higher slenderness ratios increased more in modulus of rupture (MOR) and modulus of elasticity (MOE) than did particles with lower slenderness ratios. Edge withdrawal resistance (SWRe) values did not increase with increasing slenderness ratio. 相似文献
18.
Upgrading of urea formaldehyde-bonded reed and wheat straw particleboards using silane coupling agents 总被引:3,自引:0,他引:3
Guangping Han Changwu Zhang Dongmei Zhang Kenji Umemura Shuichi Kawai 《Journal of Wood Science》1998,44(4):282-286
Reed and wheat straw particleboards bonded with urea formaldehyde (UF) resin were manufactured from two different material configurations (i.e., fine and coarse particles). The board densities were in the range of 0.550–.90g/cm3. The effects of particle size and board density on the board properties were examined. The properties of particleboard produced from fine particles were better than those made from coarse particles. An increase in board density resulted in a corresponding improvement in the board properties. The properties of OF bonded reed and wheat straw particleboards were relatively lower than those of commercial particleboards. Three silane coupling agents were used to improve the bondability between the reed and wheat particles and OF resin. Results of this study indicate that all the board properties were improved by the addition of silane coupling agent. The degree of improvement achieved from each coupling agent was different; epoxide silane was found to be more effective for reed straw particleboard, and amino silane was better for wheat straw particleboard. 相似文献
19.
20.
Effects of mat moisture content and press closing speed on the formation of density profile and properties of particleboard 总被引:1,自引:1,他引:0
Isocyanate resin-bonded 0.5 and 0.7 g/cm3 lauan (Shorea sp.) particleboards were produced from mats with uniform and distributed moisture content (MC) distributions, using three hot press closing speeds. The effects of these processing variables on the formation of density profile in particleboard and board properties were analyzed statistically. A definition of the density profile was introduced, and the correlations among the various defining factors were established. The results are summarized as follows. (1) The peak density (PD) of particleboard could be increased, with a slight reduction in the core density (CD), using mats with different MC distributions. (2) In a conventional density profile, CD and PD are highly dependent on the board mean density (MD); and the gradient factor (GF), peak distance from the faces (Pdi), and peak base (Pb) are significantly correlated to each other, at the 99% significance level. (3) Greater press closing speed reduces Pdi and Pb, with an increase in GF. (4) Greater press closing speed could increase the PD in board of low MD, with minimal effect on CD. (5) The modulus of elasticity (MOE) of particleboards from mats with high MC near the faces were consistently higher than those from mats with uniform MC, irrespective of the press closing speed, whereas their modulus of rupture (MOR) became indifferent at higher MD under slow and fast closing speeds. (6) Sanding does not improve the MOR and MOE of particleboard significantly. 相似文献